In contemporary world, the development of recent advances provides a range of options to protect your skin from sunlight like sunscreen lotions, sunscreen pills, drinkable sunscreen and even ultraviolet monitoring bracelets. There is considerable evidence showing the sun protection and prevention of UV damage to the skin by the use of different formulations of topical sunscreens. However, there have been no independent, peer reviewed, published studies on comparing these formulations.
Topical sunscreens have many limitations that culminate into noncompliance or sub-optimal use. As we all know, in order to achieve the labeled sun protection factor (SPF), a uniform application of 2 mg/cm 2 sunscreen is recommended, for which at least one teaspoon (around 3 ml) of preparation should be applied on the face, neck, and nape of the neck. But practically, most patients apply much lesser amounts, resulting in sub-optimal application thickness. Even in populations at high risk of UV-induced skin cancers, adherence to sunscreen application has been reported low despite the awareness of the benefits of sunscreen. Patients would find it much easier to take a pill rather than applying the topical sunscreen every 2–3 hours.
Ingredients commonly used in sunscreen pills are antioxidants compounds with strong anti-oxidant potential including polypodium leucotomos, Vitamin C and E, polyphenols, carotenoids, lycopene, flavonoids, proanthocyanidin, zeaxanthin, lutein , afamelanotide etc singly or in combination. These antioxidants reduce sensitivity to UV irradiation and prevent photodamage as they are free radical scavangers. Of all the ingredient, polypodium leucotomos (fern extract), ellagic acid (pomegranate extract), zeaxanthin and lutein have the antioxidant effects better when ingested and there are no studies available with their topical application. One study in 1997 concluded that Polypodium Leucotomos prevents acute sunburn and psoralen induced phototoxic reactions as well as depletion of langerhans cells in human skin. Another study in 2007 showed daily oral administration of zeaxanthin and lutein significantly decreases the number of sunburned cells after UV exposure. The latest in this league is a specific fern extract (Polypodium leucotomos), which seems to be effective to a certain extent in providing photoprotection, when taken orally. There are several studies on polypodium leucotomos showing protection against UV damage to skin and, hence it is used in several photo-aggravated dermatologic disorders such as polymorphous light eruption (PMLE), other photodermatoses, and melasma. In a randomized, double-blind, placebo-controlled human volunteer study conducted by Nestor et al., oral Polypodium leucotomos (240 mg.) was administered twice daily to 10 healthy adults for 60 days. The subjects in the treatment group showed a lesser likelihood of experiencing ≥1 episodes of sunburn, increased MED, and decreased UV-induced erythema intensity; all results being statistically significant.
Middelkamp Hup et al. conducted two separate studies to assess the efficacy of the compound as an effective chemophotoprotector against PUVA-induced skin phototoxicity. Healthy participants (n = 19) with skin phototypes II to III were exposed to UVA alone (n = 9) or with 0.6 mg/kg oral 8-methoxypsoralen (n = 10), without and after administration of 7.5 mg/kg of oral Polypodium leucotomos (PL). Clinically, a significant decrease in erythema was found in PL-treated skin after 48–72 hours.
In nearly all studies mentioned above, no significant adverse effects were reported in the PL-treated groups. Reports on clinical efficacy and safety of PL till date concludes that PL is well-tolerated at all doses administered (120–1080 mg/day) and associated with a negligible risk of side effects. One of the studies reported mild to moderate gastrointestinal complaints, and pruritus were reported only in 2% human cases.
There are no published studies to date that directly compare oral PL supplements to topical sunscreens. Moreover, oral sunscreens cannot be labeled with an SPF. González, one of the pioneering researchers of PL, has suggested that this drug offers an SPF of about 3–5; insufficient (if used alone) for most people that need sunscreen.
As per the established recommendation, PL capsules should be consumed 30 min before sun exposure, and twice daily, morning and afternoon (3 hours apart). The dose should be adjusted to weight of the subject and intensity of sunlight.
Further studies are required comparing these supplements with topical sunscreens, and also on the safety concerns including vitamin D deficiency which is otherwise proven with the use of topical sunscreen.
Hence, in a nutshell, the supplements of oral sunscreens can be used in conjunction with but not instead of topical sunscreen.